This disclosure pertains to optical imagers in general and in particular to a dual field of view refractive optical system.
Demand for imaging sensors that provide wide area surveillance is increasing. Wide area surveillance can be used in various applications such as on an unmanned aerial vehicle (UAV) platform for target recognition. Wide area surveillance can be performed at various wavelength ranges depending on the desired application. The wavelength ranges of interest include short wavelength infrared radiation (SWIR) in the wavelength range between approximately 1 μm and 3 μm, mid wavelength infrared radiation (MWIR) in the wavelength range between approximately 3 μm and 5 μm, and long wavelength infrared radiation (LWIR) in the wavelength range between approximately 8 μm and 12 μm.
In certain applications, it is desirable to provide an optical system with a dual field of view capability: a wide field of view (WFOV) optical system to achieve a large area coverage at coarser spacial resolution and a narrow field of view (NFOV) optical system to achieve a smaller area coverage at finer spacial resolution. However, providing such dual capability may be challenging especially in the case where a small light weight optical package is sought, for example, for portability on UAVs.